1. Field of the Invention
The present invention relates to devices and methods for replacing damaged biological tissue such as ligaments and tendons.
2. Description of the Prior Art
Current methods for replacement of ligaments and tendons too badly damaged to be repaired include replacement with natural biological tissue (such as skin, facia or tendon) and replacement with artificial materials.
One example of ligament reconstruction is the replacement of the anterior cruciate ligament (ACL) of the knee. The ACL provides knee stability by extending intra-articularly across the knee joint from the anteromedial surface of the proximal tibia to the posterolateral surface of the distal femur. An ACL replacement prosthesis must be implanted in the appropriate anatomical position in order to restore knee stability. This may be achieved by drilling holes in the tibia and femur that exit intra-articularly at the normal anatomic attachment sites of the ACL. An alternative to the femoral drill hole is to place the ACL replacement prosthesis over the lateral femoral condyle, which is often referred to as the "over-the-top" position.
An important problem associated with knee ligament prostheses relates to the abrasion and eventual rupture of the device. The anatomical constraints which necessitate the use of a tibial drill hole and either a femoral drill hole or an over-the-top arrangement of the ligament prosthesis also necessitate that the prosthesis be in contact with bone. This bone contact presents an unavoidable source for abrasion of the device. Abrasion rupture is the principal failure mechanism of prosthetic ligaments.